The invention relates to a check valve with a housing and a ball disposed movably therein on a guide means, which can be entrained by a flowing medium and as a result of gravity can come in contact with a seat.
A check valve of this type is disclosed in Harbison et al., U.S. Pat. No. 4,687,023 and has in a first housing member guiding means for a ball which can move in the flow passage. The two lateral guiding means are arranged substantially parallel to one another, extend into a second housing member, and are in contact with the substantially parallel inside lateral surfaces of the second housing member. The guiding means have guiding surfaces configured as curves for the ball, which are inclined inwardly and, when the check valve is installed in the horizontal position, downwardly. Above the flow passage the check valve contains a deflection chamber into which the ball is moved by the flowing medium and which necessitates a housing of comparatively large outside dimensions. The guiding means consist of the same material, namely metal, as the first housing member and it must be made comparatively large and stiff in order to avoid damage or even breakage during manufacture and assembly. This check valve cannot easily be provided with an internal lining of plastic, since lining the guiding means extending substantially freely into the second housing member would require a considerable enlargement of the outside dimensions of the check valve.
Furthermore, German Examined Application No. DE-AS 1,057,840 discloses a check valve which has two arcuate wires as tracks for guiding the ball. The ball is driven along these arcuate wires by the flowing medium into a bypass chamber. The bypass chamber requires the check valve to have relatively large outside dimensions. The check valve cannot easily be provided with a lining of plastic since the fixation and covering of the arcuate wires with a coating would entail considerable difficulty.